Plasma torches have been used for many years for cutting shapes from sheets of metal materials. Handheld plasma torches have been developed for quickly and efficiently cutting shapes from materials. While efficient in cutting material, handheld torches are limited in their accuracy to the skill of the operator. Some parts, such as those for artistic works may not need to be accurate. Other parts, such as those used in mechanical devices, often need to meet certain tolerances and need extreme accuracy. Extreme accuracy is not possible with a manually operated handheld plasma torch.
To overcome this problem, plasma torches have been developed which are designed specifically to be mounted to machines capable of controlling the torches horizontally along an x axis and a y axis. These machines can be programmed to cut shapes by inputting a system of coordinates. They can be highly accurate and produce identical parts. There are, however, a number of problems with these devices. Operation of the systems is very complex, requiring extensive training, programming of the device can be very time consuming, and small changes require reworking of the entire program. The systems are expensive and the torches themselves are more costly than the handheld torches. These problems reduce the economic gains achieved by having an automated system performing the cuts.
Other problems include accuracy and efficiency. While cutting a planar sheet of material would appear to require only movement of the torch horizontally along an x axis and a y axis, the sheets being cut may not be absolutely planar, or more likely, upon cutting, the heat generated can cause buckling of the material. As the cutting torch moves over the surface of the material, these irregularities can result in changes in the distance between the tip of the torch and the surface being cut. The changes in distance can adversely effect the accuracy of the cut. Furthermore, pressure on the tip can cause damage thereto or result in a stoppage. All of these problems can be costly in time, accuracy and money.
In conventional plasma cutting machines using computer numeric control (CNC) programming multiple time consuming creation and conversion steps are required. For example, in cutting geometric parts, the operator must draw up a design using a CAD program, or import an existing design from another CAD program. Still using the expensive CAD program, the operator must manually add pierce points and other features to the design to ready it for cutting. This step alone can take hours. Then the operator must export the drawing as a vector file from the CAD program and import the vector file into a program which is able to sort the entities and build a machine code program file. The machine code program file is then loaded into a text editing program and manually edited to cut multiple copies of parts, control kerf compensation, etc. The machine code program file is then loaded into a program that is able to transfer it by serial port to the plasma cutting machine. The machine can now run the program that it has stored in memory. Each of these steps is extremely time consuming and requires costly equipment.
Accordingly, it would be highly desirable to provide a new and improved cutting system.
It is a purpose of the invention to provide a new and improved cutting system for controlling a handheld plasma torch.
It is another purpose of the invention to provide a new and improved cutting system which is quicker and easier to use and controlled directly by a computer on which the image is generated.
It is still another purpose of the invention to provide a new and improved cutting system which moves along a z axis as well as an x axis and a y axis.
It is a further provision of the invention to provide a new and improved cutting system which can follow the contours of a sheet of material being cut.
It is still a further provision of the invention to provide a cutting system operable directly from the output of a computer generated shape.